For example, in order to conduct gene analysis, various biochemical processes and reactions, such as extraction and amplification of nucleic acids such as DNA and RNA from a sample (also called an analyte or specimen) obtained from a living thing or the like, are needed. For these processes and reactions, several reagents must be accurately mixed with the sample. When various reagents are put in the sample and various biochemical processes are carried out, the reagents must be transported to various processing cells.
As a method for mixing a reagent with a sample, a pipette system based on a dispensing robot is often used in automatic analyzing devices, etc. as described in Patent literature (PTL) 1. A dispensing robot is a unit which drives a dispensing mechanism two-dimensionally or three-dimensionally within a given area of the device and automatically sucks in and discharges a liquid through a nozzle, tip or the like at the tip of the dispensing mechanism.
On the other hand, in the field of gene analysis, there is a DNA amplifying process called PCR reaction (Polymerase Chain Reaction). In the field of gene analysis, DNA to become a template must be amplified by PCR reaction until a detector can detect it and this is known as a very effective method.
When handling DNA or RNA, it is necessary to prevent non-target DNA or RNA from getting mixed (hereinafter referred to as contamination). PCR may amplify a minute trace (one molecule) of DNA as a template. Therefore, it is necessary to prevent low-molecular clone DNA or DNA fragments (PCR product) amplified by PCR from being contaminated and becoming a template. To this end, a chamber in which DNA as a target of extraction, etc. is handled and a chamber in which PCR is conducted should be separated, and DNA aerosol contamination should be prevented by transporting a sample through a tube containing the sample, and PCR reaction should be conducted under a clean bench.
In the case of the pipette system which uses a dispensing robot as described in PTL 1, contamination is prevented by cleaning the nozzle or throwing away the tip. However, since the nozzle or tip moves in the air, it is very difficult to prevent DNA aerosol contamination. For this reason, the chamber in which DNA is handled and the chamber in which PCR is conducted are separated and work is done under a clean bench to reduce contamination as far as possible.
In recent years, researches have been promoted in which a sample is reacted with a reagent in a microspace using a microdevice to perform a series of processes including extraction, purification, amplification, and analysis of a living substance. A microdevice may be used for a wide variety of applications including gene analysis. The use of a microdevice offers the following advantages: consumption of samples and reagents is smaller than with an ordinary device; it is easier to carry than when various reagents are set; and it is disposable. In addition, since reaction in a small device is completed in an enclosed space, it is considered to address the above problem of contamination easily. PTL 2 proposes a technique of extracting DNA using a preprocessing tip as an example of application of a microdevice.